As Matches Malone and UpSideDown have stated, what matters is that the reticle is level when you shoot the rifle. There have been some vehement arguments on the hide about using bubble levels and level reticles. I am in the group that believes it is very important especially the further the distance. So, what matters is not that the reticle is level with the rifle, but that it is level to the ground and that you use a bubble level on the scope to make sure it is level to the ground when you shoot. If you don't have a level, your just guessing/eyeballing whether the reticle is level. When I compete in target shooting, I have an extreme cant of about 30 degrees on the rifle. My scope reticle is level to the earth and I use a bubble level to check. The scope sits in the rings canted 30 degrees.
Cant on rifle. My Anschutz rear sight allows me to rotate it to accomodate my cant so that my sight adjustments remain true vertical and horizontal. There is a level on the rear sight.
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